Formulation of multi-component explosives

Abstract

Process for the formulation of a multi-component explosive composition from non-detonable components comprising a defined body of unconsolidated particulate aluminum fuel granules and an oxidizing liquid. Specific particulate aluminum fuel has an average particle size within the range of about 1/64-1/4 inch and is packed within a container or other confining structure to provide an average bulk density within the range of 0.2-1.0 gm/cc. The aluminum fuel particles are generally wadded-up aluminum foil granules. The oxidizing liquid added to the body of aluminum fuel fills the void space between granules of aluminum entrapping some voids within the granules to provide an average bulk density of the mixture of oxidizing liquid and particulate aluminum within the of 1.2-1.7 gm/cc, creating an explosive, formulation which is detonable in a diameter of 4 inches at 20° C. by a one pound pentolite booster and normally by a 1/2 pound pentolite booster. The oxidizing liquid can comprise an aqueous solution of an oxidizing agent selected from the group consisting of alkali metal and ammonium nitrates, alkali metal and ammonium perchlorates, alkaline earth metal nitrates, alkaline earth metal perchlorates and mixtures thereof and may also include a hygroscopic freezing point depressant which may act as a sensitizer. An alternative oxidizing liquid for use with the particulate aluminum fuel comprises a nitroparaffin selected from the group of nitromethane, nitroethane, nitropropane and mixtures thereof. A specific oxidizing liquid is a nitromethane and nitroethane mixture having a nitromethane to nitroethane ratio of 0.6-1.2, more particularly, about 1.0.

What is claimed is: 
     
       1. In a method for formulating a multi-component explosive composition, the steps comprising: (a) providing a defined body of unconsolidated particulate aluminum fuel granules having an average particle size within the range of 1/64-1/4 inch and an average bulk density within the range of 0.2-1.0 gm/cc;   (b) providing a phase oxidizing liquid; and   (c) flooding said body of particulate aluminum fuel of step (a) with the oxidizing liquid of step (b) to provide a bulk density of said mixture of oxidizing liquid and particulate aluminum fuel mass within the range of 1.2-1.7 gm/cc and provide an explosive formulation detonable at 20° C. in a diameter of 4 inches by a one pound pentolite booster.   
     
     
       2. The method of claim 1, wherein said explosive formulation is detonable at 20° C. in a diameter of 3 inches by a 1/2 pound pentolite booster. 
     
     
       3. The method of claim 1, wherein said aluminum fuel granules are formed from chopped and wadded aluminum foil. 
     
     
       4. The method of claim 3 wherein said aluminum fuel particles have an average internal porosity within the range of 2-30 volume percent. 
     
     
       5. The method of claim 3, wherein said particulate aluminum fuel has an average surface area to volume ratio of at least 100 cm -1 . 
     
     
       6. The method of claim 1, wherein said body of aluminum fuel comprises a minor portion of atomized aluminum. 
     
     
       7. The method of claim 6, wherein said atomized aluminum has an average particle size within the range of 5-100 microns. 
     
     
       8. The method of claim 6, wherein said aluminum fuel body contains a liquid tackifying agent to promote distribution of said atomized aluminum throughout said aluminum fuel body. 
     
     
       9. The method of claim 1, wherein said particulate aluminum has a bulk density within the range of 0.3-1.0 gm/cc. 
     
     
       10. The method of claim 1, wherein said oxidizing liquid comprises a nitroparaffin selected from the group consisting of nitromethane, nitroethane, nitropropane and mixtures thereof. 
     
     
       11. The method of claim 10, wherein said oxidizing liquid comprises nitroethane. 
     
     
       12. The method of claim 1, wherein said oxidizing liquid comprises a mixture of nitromethane with a higher nitroparaffin selected from the group consisting of nitroethane and nitropropane. 
     
     
       13. The method of claim 12, wherein said oxidizing liquid comprises a mixture of nitromethane and nitroethane. 
     
     
       14. The method of claim 13, wherein the ratio of nitromethane to nitroethane in said oxidizing liquid is within the range of 0.6-1.2. 
     
     
       15. The method of claim 14, wherein the ratio of nitromethane to nitroethane is about 1.0. 
     
     
       16. The method of claim 1, wherein said oxidizing liquid component is a newtonian fluid. 
     
     
       17. The method of claim 1, wherein said oxidizing liquid component has a viscosity of no more than 100 cp at 20° C. 
     
     
       18. The method of claim 1, wherein said defined body of particulate aluminum fuel contains microbubbles interspersed with the said aluminum fuel particles. 
     
     
       19. The method of claim 18, wherein said aluminum fuel body contains a liquid tackifying agent to promote distribution of said microbubbles throughout said aluminum fuel body. 
     
     
       20. The method of claim 1, wherein said defined body of particulate aluminum is confined within an enclosed container which is vented to allow air to escape from said container as said oxidizing liquid is introduced into said container. 
     
     
       21. The method of claim 1, wherein said oxidizing liquid comprises an aqueous solution of an oxidizing agent selected from the group consisting of alkali metal and ammonium nitrates, alkali metal and ammonium perchlorates, alkaline earth metal nitrates, alkaline earth metal perchlorates and mixtures thereof. 
     
     
       22. The method of claim 21, wherein said aluminum particles are coated with a hydrophobic coating material. 
     
     
       23. The method of claim 22, wherein said hydrophobic coating material is an organosilane. 
     
     
       24. The method of claim 21, wherein the contact angle of said oxidizing liquid with respect to said particulate aluminum fuel is at least 5° to provide substantial incomplete wetting of said aluminum fuel surfaces with said oxidizer liquid. 
     
     
       25. The method of claim 21, wherein said aqueous solution comprises a hygroscopic freezing point depressant. 
     
     
       26. The method of claim 25, wherein said hygroscopic freezing point depressant is a sensitizer which functions to increase the sensitivity of said explosive composition. 
     
     
       27. The method of claim 25, wherein said hygroscopic freezing point depressant is selected from the group consisting of alcohols, polyhydric alcohols, amides, ethers, and aldehydes containing from 1-5 carbon atoms. 
     
     
       28. The method of claim 25, wherein said hygroscopic freezing point depressant is selected from the group consisting of methanol, formamide, furfural, furfural alcohol, glycols, glycol ethers and glycerins. 
     
     
       29. The method of claim 25, wherein said freezing point depressant is selected from the group consisting of methanol, ethylene glycol, propylene glycol, and glycerol. 
     
     
       30. The method of claim 25, wherein said freezing point depressant is ethylene glycol. 
     
     
       31. The method of claim 1, wherein said oxidizing liquid comprises an aqueous solution selected from the group consisting of ammonium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, magnesium nitrate, ammonium perchlorate, sodium perchlorate, potassium perchlorate, and mixtures thereof. 
     
     
       32. The method of claim 1, wherein said oxidizing liquid comprises an aqueous sodium perchlorate solution. 
     
     
       33. The method of claim 32, wherein said aqueous solution includes a hygroscopic freezing point depressant selected from the group consisting of methanol, ethylene glycol, propylene glycol and glycerol. 
     
     
       34. The method of claim 33, wherein said freezing point depressant is ethylene glycol. 
     
     
       35. The method of claim 34, wherein said aluminum fuel particles have an average internal porosity within the range of 2-30 percent. 
     
     
       36. The method of claim 35, wherein said aluminum particles are coated with a hydrophobic coating material. 
     
     
       37. The method of claim 36, wherein said hydrophobic coating material is an organosilane. 
     
     
       38. In a method for formulating a multi-component explosive composition, the steps comprising: (a) providing a defined body of unconsolidated aluminum fuel particles having an average internal porosity of at least 2 volume percent;   (b) providing an aqueous oxidizing solution of an oxidizing agent selected from the group consisting of alkali metal and ammonium nitrates, alkali metal and ammonium perchlorates, alkaline earth metal nitrates, alkaline earth metal perchlorates and mixtures thereof in an aqueous solution comprising a mixture of water and a hygroscopic freezing point depressant for water; and   (c) flooding said body of aluminum fuel particles of step (a) with the oxidizing solution of step (b) to provide a bulk density of said mixture of oxidizing solution and particulate aluminum fuel mass within the range of 1.2-1.7 gm/cc to provide an explosive formulation detonable at 20° C. in a diameter of 4 inches by a one pound pentolite booster.   
     
     
       39. The method of claim 38, wherein said oxidizing agent is selected from the group consisting of ammonium nitrate, sodium nitrate potassium nitrate, calcium nitrate, magnesium nitrate, ammonium perchlorate, sodium perchlorate, potassium perchlorate, and mixtures thereof. 
     
     
       40. The method of claim 39, wherein said aqueous agent comprises sodium perchlorate present in a predominant amount. 
     
     
       41. The method of claim 40, wherein said freezing point depressant is selected from the group consisting of methanol, ethylene glycol, propylene glycol, and glycerol. 
     
     
       42. The method of claim 41, wherein said freezing point depressant is ethylene glycol. 
     
     
       43. The method of claim 42, wherein said aluminum fuel particles are formed from aluminum foil. 
     
     
       44. The method of claim 38, wherein said defined body of aluminum fuel contains microcells interspersed with said aluminum fuel particles. 
     
     
       45. The method of claim 38, wherein said aluminum fuel particles are provided with a hydrophobic coating material. 
     
     
       46. The method of claim 45, wherein the contact angle of said oxidizing liquid with respect to the surfaces of said aluminum fuel particles is at least 5° to provide incomplete wetting of said metal fuel surfaces with said oxidizer liquid. 
     
     
       47. The method of claim 38, wherein said particulate aluminum fuel has an average surface area to volume ratio of at least 100 cm -1 . 
     
     
       48. The method of claim 38, wherein said liquid fuel component has a viscosity of no more than 100 cp at 20° C.